ACR Editing

[kdoc856]

Can anyone point me to good reading sources or enlghten me with exactly how the features in the ACR editor work? Specifically, the difference between exposure vs. brighten, black vs contrast, what clarity does vs sharpening, vibrance vs saturation? Thanks much.

Kevin

[FrankMi]

Hi Kevin, I'm not sure where I found this but it should provide a good starting point for discussion. It should help answer the differences questions you are asking as well as provide a workflow for using Adobe Camera Raw.

As other's chime in, it may give me an opportunity to correct any deficiencies there may be in this list.

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You start your workflow in ACR in the Basic Panel by making the following adjustments:

1. White Balance – The options available can be used to set the Temperature and Tint values based on the lighting selected. This control starts out set to As Shot Temperature and Tint values. When Custom is indicated, the Temperature and Tint values have been manually set below. You may want to start by selecting a White Balance option here then fine tune the Temperature and Tint below. You can also set the White Balance with White Balance eye dropper tool by selecting a neutral color such as white or gray.

2. Temperature – This slider lets you set the Kelvin Temperature of the light. To the right produces a warmer tint (Yellow), to the left produces a cooler tint (Blue).

3. Tint - To the right adds a little Magenta and to the left adds a little Green to the image.

4. Exposure – Exposure is used to adjust the clipping point for highlights. As you move the slider to the right, the photograph will brighten. As you move it to the left, the photograph will darken. Exposure determines where the lightest pixels will clip (any pixel that is bright or brighter in the photograph will be changed to 255).

All other tones relative to the new white point, including the middle tones and shadows, will be smoothly adjusted. You can use the right hand side of the Histogram to determine where the clipping is taking place or visually, try to get a balance that produces the greatest detail in both the highlights and shadows. If you hold down the ALT key and move this slider, you will be able to see exactly what is changing to full white and loosing detail as a result.

5. Recovery – Helps bring details back into the highlights if they are available but it can also produce muddy highlights in overexposed areas if too much is used. If you hold down the ALT key and move this slider, you will be able to see exactly what is changing from full white and increasing detail as a result.

6. Fill Light – Increases detail in the mid-shadows similar to using a fill card to bounce light into the midrange shadows. If you go too far the image will start to turn hazy and fog the image.

7. Blacks – Makes the shadows darker. If you hold down the ALT key and move this slider, you will be able to see exactly what is changing to full black and loosing detail as a result.

8. Brightness - Brightness focuses its attention on the middle tones. When you make a positive Brightness adjustment, the brighter pixels are compressed and the darker tones are expanded. A negative Brightness adjustment reverses the effect on the photographs tones.

The highlights are expanded and the shadows are compressed. If you set the Exposure first, then, if necessary, Recover before you adjust Brightness, the Brightness slider is more likely to reduce contrast in either the highlights or the shadows and the image will have more ‘pop’. When you compress tones in part of the tonal range, such as compressing the highlights with a positive Brightness setting, you lose contrast among those tones. The highlights will be brighter, but they will also have less contrast than they otherwise might if Exposure was used instead. Likewise, when you make a negative Brightness adjustment, the photograph will darken but your shadows will appear flatter than if you used the Exposure slider with a negative value.

9. Contrast – Makes the highlights whiter and the shadows blacker.

10. Clarity – Clarity adjusts the mid-range contrast which make the image look sharper. If you plan to sharpen the image in Photoshop, minimize or completely avoid the use of this control. To the right sharpens the mid-tomes, to the left softens the mid-tones.

11. Vibrance – Vibrance can make the mild colors brighter without clipping at the maximum setting. If it is moved too far right it can cause incorrect colors to appear where they didn’t previously exist.

12. Saturation – Saturation affects all colors and can drive the colors to clip out all detail at maximum. To the right produces stronger colors and can easily become excessive, to the left reduces the colors all the way to a black and white image.

[kris]

Hy,

there are several books on RAW, and also articles on WEB.

One I really found superb is
http://www.eyrolles.com/Audiovisuel/...-9782212122831

Here you can understand the RAW and how to develop it.

More specific to Camera Raw I used
http://www.eyrolles.com/Audiovisuel/...-9782212127416

Both books are in French, but maybe you can find an English version.

Bye
Andrea

[kdoc856]

Thanks very much. I use the ACR all the time and have generally been pleased with it, but realized cant really explain it to anyone else. If you cant explain it, you dont understand it. Will pursue the info and sources.

Thanks very much

Kevin

[herbert]

@Frank,

Great summary.

10. Clarity – Clarity adjusts the mid-range contrast which make the image look sharper. If you plan to sharpen the image in Photoshop, minimize or completely avoid the use of this control.

Really?

Clarity is a tool for adjusting the local contrast. It is similar to performing a wide radius unsharp mask (e.g. settings such as 15,100,0, 17,50,0, etc.) However Clarity is applied to the luminance channel only, so you don't get the saturation effect as with a large radius small amount USM.

I think its use does not conflict with sharpening since it is working at a different level to edge sharpening. Just be sure to keep it in check because images can become very gritty looking with excess texture. It definitely adds pop to an image.

I don't usually do sharpening in PS so maybe I have not noticed any issues. I will keep an eye out in future.

Alex

[FrankMi]

Really?

Clarity is a tool for adjusting the local contrast. It is similar to performing a wide radius unsharp mask (e.g. settings such as 15,100,0, 17,50,0, etc.) However Clarity is applied to the luminance channel only, so you don't get the saturation effect as with a large radius small amount USM.

I think its use does not conflict with sharpening since it is working at a different level to edge sharpening. Just be sure to keep it in check because images can become very gritty looking with excess texture. It definitely adds pop to an image.

I don't usually do sharpening in PS so maybe I have not noticed any issues. I will keep an eye out in future.

Alex

Hi Alex, one of the reasons for posting this in response to Kevin' request was to hopefully find out if the information was valid and/or needed further clarification. Thanks for the comments!

Is the information accurate enough to help Kevin and anyone else that looks at it?

[herbert]

Is the information accurate enough to help Kevin and anyone else that looks at it?

Yes. I think it is a great introduction to camera raw. It provides enough to let the user know what each slider affects. They can then start to learn by trying it out.

If they are really interested in the details then they can ask Google or CiC.

[Colin Southern]

The industry standard reference book for camera RAW is http://www.amazon.com/Real-World-Cam...1407529&sr=1-1 (written by two gents who had a lot of input into ACR's development).

[mastamak]

Thank you, Frank, for taking the time to prepare that very comprehensive outline of ACR. Very helpful

Grant

[Crovean]

Kevin,

here's a good video on how to work around the toggle switch using photoshop LR3.

I posted it on my website so that I don't have to look for it again hehehehe.

It's more in dept but very informative.